Name

BackhandSelfRedirect

Synopsis

BackhandSelfRedirect <On|Off>
Default Off  
Directory

A common way to run Apache when heavily loaded is to have two instances of Apache running on the same server: one serving static content and doing load balancing and the second running CGIs, typically with mod_perl or some other built-in scripting module. The reason you do this is that each instance of Apache with mod_perl tends to consume a lot of memory, so you only want them to run when they need to. So, normally one sets them up on a different IP address and carefully arranges only the CGI URLs to go to that server (or uses mod_proxy to reverse proxy some URLs to that server). If you are running mod_backhand, though, you can allow it to redirect to another server on the same host. If BackhandSelfRedirect is off and the candidacy functions indicate that the host itself is the best candidate, then mod_backhand will simply “fall through” and allow the rest of Apache to handle the request. However, if BackhandSelfRedirect is on, then it will redirect to itself as if it were another host, thus invoking the “heavyweight” instance. Note that this requires you to set up the MulticastStats directive to use the interface the mod_perl (or whatever) instance to which it’s bound, rather than the one to which the “lightweight” instance is bound.

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